The invention relates to a recovery method and installation for the heat contained in a solid body occurring in divided form, and applies more especially to the cooling of the ash from lean fuels.
Lean fuels like bony coal and oil shale have an ash content higher than 50%. This ash, which must be periodically removed, contains a quantity of heat which represents a considerable fraction of the energy initially contained in the fuel, of the order of 25 to 50%. It is therefore advantageous to recover this heat in cooling equipment in which the ash is cooled by a gas, generally air, which is thus heated and can itself serve in a recovery circuit, such as a boiler.
However, the granulometric spectrum of the ash is generally rather extended, and it has been observed that the yield of cooling equipment of different types was optimal only when the latter were supplied by substances occurring within a rather precise granulometric range.